今日更新:Composites Part A: Applied Science and Manufacturing 2 篇,Composites Part B: Engineering 1 篇,Composites Science and Technology 1 篇
Breadth-first search algorithm on the finite element simulation of the electrical resistivity of the carbon black elastomeric pressurized sensor
Mojtaba Haghgoo, Alireza Alidoust, Reza Ansari, Jamaloddin Jamali, Mohammad Kazem Hassanzadeh-Aghdam
doi:10.1016/j.compositesa.2024.108523
宽度优先搜索算法在炭黑弹性加压传感器电阻率有限元模拟中的应用
Resistivity and piezoresistive sensitivity of Carbon Black (CB) elastomeric nanocomposites are studied using a finite element method with a conductive network model. CB spheres are placed into Representative Volume Elements (RVEs) in random positions to perform simulations and obtain the strained state and new position of particles. Numerical results are implemented into a breadth-first search algorithm tailored to find percolation pathways from one end of the RVE to another based on the shortest distance between CBs in the strained regime. Percolation pathways are used by the conductive network model to determine the critical distance for resistivity. Resistivity diminishes as the critical distance increases attributed to a greater number of electrons penetrating the barriers. Critical distance at which tunneling can occur expands with an increase in barrier potential. Smaller CBs that can more efficiently occupy the gaps lead to a reduction in the critical distance range necessary for percolation to happen.
采用基于导电网络模型的有限元方法研究了碳黑弹性纳米复合材料的电阻率和压阻灵敏度。将CB球置于随机位置的代表性体积单元(RVEs)中进行模拟,得到了粒子的应变状态和新位置。数值结果被实现到一个宽度优先的搜索算法中,该算法基于应变状态下CBs之间的最短距离来寻找从RVE一端到另一端的渗透路径。导电网络模型利用渗透路径来确定电阻率的临界距离。电阻率随着临界距离的增加而减小,这是由于穿透势垒的电子数量增加所致。发生隧穿的临界距离随势垒势的增加而扩大。较小的cb可以更有效地占据间隙,从而减少发生渗透所需的临界距离范围。
Using higher rates of stabilization of a wet-spun pan fibre to understand the effect of microstructure on the tensile and compressive properties of carbon fibre
Nguyen Le Thao Nguyen, Maxime Maghe, Pablo Mota-Santiago, Srinivas Nunna, Claudia Creighton, Russell J. Varley
doi:10.1016/j.compositesa.2024.108524
利用高稳定化率的湿纺pan纤维,了解微观结构对碳纤维拉伸和压缩性能的影响
The transformation of a polyacrylonitrile (PAN) precursor fibre into carbon fibre using varying stabilization times during carbon fibre manufacture is presented in this work. The wet-spun precursor fibre is a specifically designed PAN co-polymer made up of acrylonitrile, methyl acrylate and 3 wt% itaconic acid. The residence or stabilization times in the oxidation ovens are varied from 32, 64 and 96 min, enabling investigation of the impact upon microstructure upon tensile and compressive properties. Using a continuous pilot scale carbonization line for faster cyclization and dehydrogenation, the precursor fibres exhibited lower oxygen uptake contributing to the formation of a less dense and more amorphous carbon fibre. Synchrotron based SAXS-WAXS characterisation and Raman spectroscopy of the carbon fibre microstructure displays lower orientation and crystallinity, with higher void concentration. This led to lower electrical conductivity, lower tensile strength (19 %) but higher compressive strength (27 %) when reducing stabilisation times from 96 to 32 min.
在碳纤维制造过程中,采用不同的稳定时间将聚丙烯腈(PAN)前驱体纤维转化为碳纤维。湿纺前驱纤维是一种专门设计的PAN共聚物,由丙烯腈、丙烯酸甲酯和3 wt%衣康酸组成。在氧化炉中的停留或稳定时间从32、64和96 min不等,从而可以研究对微观结构、拉伸和压缩性能的影响。采用连续的中试炭化线进行快速的环化和脱氢,前驱体纤维表现出较低的氧吸收率,有助于形成密度更低、更无定形的碳纤维。基于同步加速器的SAXS-WAXS表征和拉曼光谱分析表明,碳纤维微观结构的取向和结晶度较低,空洞浓度较高。当稳定时间从96分钟减少到32 分钟时,导致电导率降低,抗拉强度降低(19 %),但抗压强度提高(27 %)。
Effects of Electron Beam and Atomic Oxygen Irradiation on Hypervelocity - Impact tested / Polyimide Coated Carbon Fiber-reinforced Plates
Masahiro Nishida, Daichi Kimura, Kyouko Ashida, Naomasa Furuta, Yoshiaki Iwase, Yuichi Ishida
doi:10.1016/j.compositesb.2024.111877
电子束和原子氧辐照对超高速冲击试验/聚酰亚胺涂层碳纤维增强板的影响
In a low-Earth orbit, space debris orbit at approximately the first cosmic velocity. When space debris strike a spacecraft, ejecta (fragments) from the spacecraft are widely scattered. The reduction in the number of ejecta (fragments caused by impact) must also be considered when selecting spacecraft materials. The authors’ group has previously examined the size of ejecta (fragments) and reduction in the number of ejecta. In general, the mechanical properties of polymer materials and CFRP plates may be damaged by space environments, such as radiation (gamma rays and electron beams (EBs)), atomic oxygen (AO), ultraviolet rays, temperature, and thermal cycling. The authors suggested an anti-AO coating/polyimide CFRP as a material resistant to space environments. The effects of EB and AO irradiation on the fracture behavior and ejecta of anti-AO coating/polyimide CFRP were examined for hypervelocity impacts. The results of static three-point flexural tests were compared with the fracture behavior and ejecta. A two-stage light-gas gun was used for the impact tests. Spherical projectiles formed of aluminum alloy 2017-T4 with a diameter of 1.6 mm were used. Photographs of the ejecta scattered in front of each polyimide CFRP plate were captured from the side using a high-speed video camera. The number and weight of the ejecta on the front side and perforation holes were examined.
在近地轨道上,空间碎片以大约第一宇宙速度运行。当太空碎片撞击宇宙飞船时,宇宙飞船的弹射物(碎片)会广泛分散。在选择航天器材料时,还必须考虑减少弹射物(撞击产生的碎片)的数量。作者小组先前已经检查了喷射物(碎片)的大小和喷射物数量的减少。一般来说,空间环境的辐射(伽马射线和电子束(EBs))、原子氧(AO)、紫外线、温度、热循环等都会破坏高分子材料和CFRP板的力学性能。作者提出了一种抗ao涂层/聚酰亚胺CFRP作为抗空间环境的材料。研究了EB和AO辐照对抗AO涂层/聚酰亚胺CFRP的超高速冲击断裂行为和弹射量的影响。将静态三点弯曲试验结果与断裂行为和弹射进行了比较。两级轻气 枪用于冲击试验。采用直径为1.6 mm的2017-T4铝合金球型弹丸。利用高速摄像机从侧面捕捉到分散在每个聚酰亚胺CFRP板前面的抛射物的照片。对前侧孔和射孔的弹射物数量和重量进行了检测。
Multifunctional Superhydrophobic Composite Film with Icing Monitoring and Anti-icing/Deicing Performance
Chao Yang, Haozhong Ji, Longhai Song, Haoxi Su, Zhengpan Qi, Yao Wang, E. Cheng, Libin Zhao, Ning Hu
doi:10.1016/j.compscitech.2024.110916
具有结冰监测和防结冰/除冰性能的多功能超疏水复合膜
Icing can cause damage to outdoor equipment such as airplanes, wind turbine blades and power lines, which poses potential safety hazards. Recently, electrothermal superhydrophobic composite film with the synergistic effect of anti-icing and deicing properties can effectively hinder the formation and accumulation of ice. However, these superhydrophobic composite films have no icing condition monitoring property, which is critical to improve deicing efficiency and reduce energy consumption. In this paper, we have designed a multifunctional superhydrophobic composite film using the combination of laser ablation and spraying method, which exhibits excellent comprehensive anti-icing, deicing and icing monitoring properties. The experimental results demonstrated the icing delay time of the film reached 4.0 min at -20 °C. Meanwhile, taking advantage of the outstanding electrothermal effects of the laser induced graphene/carbon nanotubes (LIG/CNTs) composite conductive network, with DC voltage (5 V) excitation, the film temperature rapidly rose from -20 °C to 107 °C in 90 s, thereby effectively removing the ice. More importantly, due to the temperature sensing performance of the LIG/CNTs composite conductive network, it could monitor whole icing and deicing process of droplet with different volumes and temperatures in real time through the change of film resistance. Therefore, the comprehensive anti-icing, deicing and ice monitoring properties allowed it to effectively reduce icing hazards.
结冰会对飞机、风力涡轮机叶片、电力线等户外设备造成损坏,存在安全隐患。近年来,具有防冰和除冰性能协同作用的电热超疏水复合膜可以有效地阻碍冰的形成和积聚。然而,这些超疏水复合膜不具备结冰状态监测性能,这对提高除冰效率和降低能耗至关重要。本文采用激光烧蚀和喷涂相结合的方法设计了一种多功能超疏水复合膜,具有优异的综合防冰、除冰和结冰监测性能。实验结果表明,在-20℃条件下,膜的结冰延迟时间达到4.0 min。同时,利用激光诱导石墨烯/碳纳米管(LIG/CNTs)复合导电网络突出的电热效应,在直流电压(5 V)激励下,薄膜温度在90 s内从-20℃迅速上升到107℃,从而有效地去除了冰。更重要的是,由于LIG/CNTs复合导电网络的感温性能,它可以通过膜电阻的变化实时监测不同体积和温度的液滴的整个结冰和除冰过程。因此,综合的防冰、除冰和冰监测性能使其能够有效降低结冰危害。